<?php
$estimate = store_transaction_calc_gross($txn);

if (variable_get('paypal_min_amount', '5.00') > $estimate) {
  form_set_error('gross', t('Your purchase total must be at least %min-purchase-amount for Paypal purchases.', array('%min-purchase-amount' => payment_format(variable_get('paypal_min_amount', '5.00')))));
}

